Antibodies have profound relevance as research tools and in diagnostic and therapeutic applications. However, the identification of useful antibodies is difficult and once identified, antibodies often require considerable redesign or “humanization” before they are suitable for therapeutic applications in humans.
Many methods for identifying antibodies involve display of libraries of antibodies derived by amplification of nucleic acids from B cells or tissues. Some of these methods have utilized synthetic libraries. However, many of these approaches have limitations. For example, most human antibody libraries known in the art contain only the antibody sequence diversity that can be experimentally captured or cloned from a biological source (e.g., B cells). Accordingly, such libraries may over-represent some sequences, while completely lacking or under-representing other sequences, particularly those binding human antigens. Most synthetic libraries known in the art have other limitations, such as the occurrence of unnatural (i.e., non-human) amino acid sequence motifs that have the potential to be immunogenic.
Accordingly, a need exists for diverse antibody libraries that contain candidate antibodies that are non-immunogenic (i.e., are human) and have desired properties (e.g., the ability to recognize a broad variety of antigens). However, obtaining such libraries requires balancing the competing objectives of generating diverse libraries while still maintaining the human character of the sequences within the library. The current invention provides antibody libraries that have these and other desirable features, and methods of making and using such libraries.